DeadPurpleDog

Have been searching for a ZR1 and something I keep hearing is that the cars(similarly equipped) can perform very differently and that that's the nature of the engines. Is this true, or are the cars, for practical purposes, really similar? If true, when purchasing long distance, is there any way to tell?

Aurora40

It seemed to me like magazines in the 90's started that. My guess is it's more that those guys don't know how to launch high-powered cars very well, and thus had fairly inconsistent times. The engines were pretty carefully checked and assembled.

From what I've seen of owners who have drag raced them, the times they put down don't seem to vary too widely, especially the trap speeds.

DeadPurpleDog

Thanks Aurora40, that's helpful. I haven't been able to find what I want in So Cal and am trying to sift through them long distance.

terryszr1

let the guys know what your looking for and they might be able to help you . i have 2 z and when i dynod them stk one had 331.9 rwhp and the other 337.6 both had over 100k on them and going strong . these are great motors built to last

DeadPurpleDog

Never had a car dyno'd, Terry. I'm having local Chevy deale3rs check out the cars I'm interested in. . can they do a dyno checks. . and can they be done without any risk to the cars?. . the owners are understandably touchy

LPE385

I think what DeadPurpleDog is referring to is people talk about the cam timing on these cars. Depending on the cam timing from the factory you could have a car with more low end tq, mid range, or upper rpm hp.

Like others have said you could have the car dynoed, that will give a little idea but not everyone is going to be able to take their car to the dyno. Again every car is different so have fun.

DeadPurpleDog

Didn't know cam timing was possible and has that effect. I spoke with the people at Guldstrand and they said the main challenge with these engines is at lower RPM's, and said a huge difference can be achieved through changing the gearing. Do you agree?

xlr8nflorida

Anything can happen on a dyno but I wouldn't sweat it

These engines are bullet proof.

GTB/ZR-1

Absolutely... 4.10 gearing really wake the cars up. The stock 3.45 gear is a bit tall for the admittedly heavy, somewhat peaky car.

An equally responsive performance mod is, long tubes & an X-pipe--approx 30HP or more

DeadPurpleDog

Thanks for the suggestion. . is this a very expensive mod?

LPE385

Just like GTB said, 4:10's will really wake the car up.

Its not that expensive but like its been said, long tube headers, exhaust, gears, and chip will totally change the performance of the car. The cost is appox. $3,500 depending on labor and its well worth it.

Aurora40

I recall Marc H had mentioned that using the cam timing pins, I think you could have about 2* or so of variation? He mentioned that you could probably have about a 10hp spread depending on how the exhaust and intakes ended up relative to each other. I don't recall the degrees as much as I recall the power difference he mentioned.

Some of the magazines made it sound like the motors made anywhere from 350hp to 450hp. They had some wildly different 1/4 mile times from 12.8's to 13.6's. I suspect this really is because many don't make any adjustments for ambient conditions, and because many of them can't drive for crap. I'd love to see magazines include 60' times with their 1/4 mile times.

glass slipper

Yes, you can change cam timing as far as intake/exhaust centerline and lobe separation angle (your choice of two of the three) but not duration (advertised or .050"). I don't know who you spoke to at Guldstrand, but these engines are not your typical DOHC engine with no power at lower RPMs. With the secondary system on the LT5, they pull like a tractor at low RPMs. If you want proof, I'll give you a ride in my bone stock '93 and take it down to 25 MPH in 6th (~500 RPM) and let you see how smoothly it pulls away...no bucking, hesitation, coughing, sputtering, lugging or anything. Just amazing!

terryszr1

if one od us gave you a ride ,you would undersyand why we all have one of these.feeling very lucky to own a piece of history. the acceleration is what gives us : and nothing sounds like it . where are you in so cal . maybe one of us could give you a first hand demo. we love showing off .my blk car has a fully ported 350 410 gears and has run 11.57@!@123.6 @famoso in bakersfield

DeadPurpleDog

Wow. . what a generous offer, Terry. This is my first post here and I could not have guessed at what a warm, welcoming group you are! I'm in Orange County and travel all over Southern California weekly.

Aurora40

The LT5 had more torque than the L98 at every rpm point.



That said, with the very wide rpm range, they certainly can use more gear in the rear.

terryszr1

I will be in orange co on tues cking out the tune on my car to get ready for famoso feb 15 -16 test and tune. if youd like maybe we can meet somewhere for a little fun drive. pm me what might be a good time for you .the only trouble will be i think you will get a jones to own one for yourself .

terryszr1

will be leaving for la about 10 am. please pm me if youd like to meet

DeadPurpleDog

Thanks, again, for your generous offer. I'd enjoy experiencing your ZR1. Unfortunately I'm struggling to recover from a nasty bout of the flu and am still trying to run a business from home in between coughs and sneezes! Thanks, again, and best wishes for a safe journey!

94ZR1

Most variations are due to the driver not being used to driving a high RPM, DOHC, 4 valve engine